Room-temperature quantum cloning machine with full coherent phase control in nanodiamond

Area of Science:

• Quantum Information Science
• Solid-State Physics
• Quantum Cryptography

Background:

• The no-cloning theorem prohibits perfect ideal cloning of unknown quantum states.
• Approximate or probabilistic quantum cloning is crucial for various quantum technologies.
• Phase quantum cloning is particularly relevant for attacking quantum key distribution protocols like BB84.

Purpose of the Study:

• To report the first room-temperature implementation of quantum phase cloning.
• To demonstrate a controllable phase in a solid-state system for quantum cloning.
• To investigate the feasibility of phase cloning for qubits on the Bloch sphere equator.

Main Methods:

• Utilized a nitrogen-vacancy (NV) center in a nanodiamond as a solid-state quantum phase cloning machine.
• Implemented the phase cloner at room temperature.
• Controlled and measured the phase of the cloned qubits with high accuracy.

Main Results:

• Achieved successful room-temperature quantum phase cloning in a solid-state NV center system.
• Demonstrated controllable phase with high accuracy for qubits on the equator of the Bloch sphere.
• Experimental results align with theoretical predictions for phase quantum cloning.

Conclusions:

• This work presents the first room-temperature solid-state implementation of quantum phase cloning.
• The developed phase cloner offers controllable phase and high accuracy, suitable for qubits on the Bloch sphere equator.
• This experiment lays the foundation for developing phase-controllable quantum information devices and enhances quantum communication security.